KR101000698B1 - Flame retardant polymer composition comprising polyolefin with high molecular weight distribution - Google Patents

Abstract

The present invention relates to a flame retardant polymer composition, comprising (A) a polyolefin comprising a polyolefin with a molecular weight distribution M w /M n > 20, (B) a silicone-group containing compound, and (C) an inorganic filler material, to an article, in particular a wire or cable, comprising said flame retardant polymer composition, and to the use of said composition for the production of a layer of a wire or cable.

Description

Flame-retardant polymer composition containing polyolefin with high molecular weight distribution {FLAME RETARDANT POLYMER COMPOSITION COMPRISING POLYOLEFIN WITH HIGH MOLECULAR WEIGHT DISTRIBUTION}

The present invention relates to a flame retardant polymer composition, an article containing said flame retardant polymer composition, in particular a wire or cable, and the use of said composition for producing a layer of wire or cable.

Several approaches to improving the flame retardancy of polymers are known in the art. First, a method of including a compound containing a halide in a polymer is known. However, a disadvantage of these materials is that when burned, harmful corrosive gases, such as hydrogen halides, are delivered. This is also a disadvantage of flame retardant polymer compositions based on PVC.

In a further approach, the flame retardant composition comprises a relatively large amount of inorganic filler, usually hydrated compounds and hydroxide compounds, for example, in the range of 200 to 600 ° C. during combustion. It is endothermically decomposed at temperature to generate an inert gas. Such inorganic fillers include Al (OH) ₃ and Mg (OH) ₂ . However, these flame retardant materials have a disadvantage that the high content of the filler reduces the processability and mechanical properties of the polymer composition and the cost of the inorganic filler is high.

The third approach uses silicone fluids or gums in the composition, together with organic polymers containing ethylene acrylate or acetate copolymers, and inorganic fillers, as disclosed in EP 0 393 959. Although these compositions have good flame retardant properties, melt fracture often occurs when the composition is extruded into a cable layer, and there is room for improvement in processability of the composition. In addition, the surface quality of the extruded cable layer is often poor, which also requires further improvement.

It is therefore an object of the present invention to provide flame retardant polymer compositions which avoid the disadvantages of prior art materials and exhibit a combination of good flame retardancy, good processability such as extrudability, and good mechanical properties such as improved surface quality.

The present invention provides a process for the processability and surface quality of polymer compositions comprising organic polymers, silicone group containing compounds, and inorganic filler materials to contain polyolefins, i.e., olefin mono- or copolymers having high molecular weight distributions, typically greater than 20. It is based on the finding that it can be improved.

Therefore, the present invention,

(A) a polyolefin comprising a polyolefin having a molecular weight distribution M _w / M _n > 20,

(B) a silicon-group containing compound, and

(C) inorganic filler material

It provides a flame retardant polymer composition containing.

As can be seen from the improved extrusion behavior when the composition is extruded as a layer of wire or cable, the compositions of the present invention exhibit improved processability. In addition, the extruded layer has good / improved surface quality.

Preferably, the composition is free of halogen- and phosphorus-containing compounds as flame retardant aids, although these compounds are present in the composition in amounts of less than 3000 ppm.

More preferably, the composition is free of halogen-containing compounds. However, especially phosphorus containing-compounds may be present as stabilizers in the composition, usually in amounts of less than 2000 ppm, more preferably less than 1000 ppm.

Within the composition, components (A) to (C), and any component (D) as follows, may consist of a single chemical compound or a mixture of compounds of the required type.

In addition, the term "polyolefin" (or "polyethylene") herein means both olefin mono- or copolymers (or ethylene mono- or copolymers).

In the composition of the present invention, preferably the amount of component (A) is 30 to 70% by weight of the total amount of the polymer composition, more preferably 40 to 60% by weight of the total amount of the composition.

Preferably component (A) comprises a polyolefin having a molecular weight distribution M _w / M _n > 20, more preferably> 22, most preferably> 25, more preferably consisting of it.

Preferably, the polyolefin (A) having a high molecular weight distribution is produced in a high pressure process, i.e. without the use of a coordination catalyst, usually under a pressure of at least 50 MPa.

Also preferably, an autoclave reactor is used to produce the polyolefin (A).

Also preferably, component (A) comprises a polyolefin having a g 'value of 0.35 or less, more preferably constituted thereby.

Preferably, component (A) comprises, and more preferably consists of, a polyolefin having a shear thinning index (SHI) eta _0.05 / eta ₃₀₀ of at least 70.

Component (A) is formed by polyolefins, ie olefins, preferably ethylene, mono- and / or copolymers. Such polyolefins include, for example, homopolymers or copolymers of ethylene, propylene, and butenes, and polymers of butadiene or isoprene. Suitable homopolymers and copolymers of ethylene include low density polyethylene, linear low density, medium density, or high density polyethylene, and ultra low density polyethylene. Suitable ethylene copolymers are C ₃ -to C ₂₀ -alpha-olefins, C ₁ -to C ₆ -alkyl acrylates, C ₁ -to C ₆ -alkyl methacrylates, acrylic acid, methacrylic acid, and vinyl acetate Copolymers. Preferred examples of alkyl alpha-olefins are propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, and 1-octene.

In the composition of the invention, preferably, component (A) comprises a polyolefin having a polar group, more preferably consists of it.

Polyolefins with polar copolymers, more preferably polyethylene, are preferably produced by copolymerization of polar comonomers and olefin monomers. However, it may also be produced by grafting polyolefins, for example by grafting acrylic acid, methacrylic acid, or maleic anhydride onto the polyolefin.

Preference is given to introducing the polar group into the polyolefin by copolymerization of the olefin monomer with an appropriate comonomer having a polar group.

Also preferably, the polar copolymer comprises one or more comonomers and olefins selected from C ₁ -to C ₆ -alkyl acrylates, C ₁ -to C ₆ -alkyl methacrylates, acrylic acid, methacrylic acid, and vinyl acetate, Preferably a copolymer of ethylene. The copolymer may also include an ionomer structure (such as, for example, DuPont's Surlyn type).

Also preferably, the polar copolymer is an olefin / acrylate, and / or olefin / acetate copolymer, more preferably ethylene / acrylate, and / or ethylene / acetate.

Also preferably, the polar copolymer comprises a copolymer of C ₁ -to C ₄ -alkyl acrylate or vinylacetate such as methyl, ethyl, propyl, or butyl and an olefin, preferably ethylene.

In a particularly preferred embodiment, component (A) of the polymer composition used in the flame retardant layer is selected from the group consisting of olefins, preferably ethylene, with at least one comonomer selected from the group of unsubstituted or substituted acrylic acids according to formula (I). Preferably, the copolymer or copolymer mixture comprises at least 25% by weight, more preferably at least 35% by weight, and most preferably consists of:

Wherein R is H or an organic substituent, preferably R is H or a hydrocarbon substituent.

More preferably the type of comonomer is selected from the group of acrylic acid according to formula (I), wherein R is H or an alkyl group, more preferably R is H or a C ₁ -to C ₆ -alkyl substituent.

Particular preference is given to the polar polyolefins comprising copolymers of acrylic copolymers and ethylene, for example ethylene acrylic acid or methacrylic acid copolymers, most preferred is ethylene methacrylic acid copolymers.

The amount of comonomer having a polar group in the olefin copolymer is preferably 2 to 40% by weight, more preferably 4 to 20% by weight, most preferably 6 to 12% by weight.

In addition to the olefins and other comonomers defined above, the copolymer may also comprise additional monomers. For example, acrylate and acrylic acid or methacrylic acid, or vinyl silane and acrylate, or siloxane and acrylate, or terpolymer between siloxane and acrylic acid can be used.

These copolymers can be crosslinked after extrusion, for example by irradiation. Silane-crosslinkable polymers, ie polymers prepared using unsaturated silane monomers with hydrolyzable groups capable of crosslinking by hydrolysis and condensation in the presence of water and optionally silanol condensation catalysts to form silanol groups Can also be used.

Also preferably the polyolefins having polar groups account for at least 30%, more preferably at least 50%, even more preferably at least 70% by weight of component (A). Most preferably, component (A) consists entirely of polyolefins with polar groups.

The composition further contains a silicone-group containing compound (B).

In a preferred embodiment of the composition of the invention, component (B) is an olefin, preferably an ethylene copolymer, or any mixture of these compounds comprising a silicone fluid or gum, or at least one silicone-group containing comonomer .

Preferably, the comonomer is vinyl polysiloxane, for example vinyl unsaturated polybishydrocarbylsiloxane.

And a silicone fluid, and is well-known black suitable for use in the present invention, such as _{R 3 SiO 0 .5, R 2} SiO, R 1 SiO 1 .5, R 1 R 2 SiO 0 .5, RR 1 SiO, R _{¹ 2} SiO, RSiO ¹ _.5, and SiO ₂ units and containing an organic polysiloxane polymer containing a unit when the siloxane compound with a chemical selected from the group consisting of and mixtures thereof, each R here is a saturated or unsaturated 1 independently represents a hydrocarbon radical, and each R ¹ represents a radical such as R or a radical selected from the group consisting of hydrogen, hydroxyl, alkoxy, aryl, vinyl, or allyl radicals.

Preferably, the organopolysiloxane has a number average molecular weight M _n of about 10 to 10,000,000. Molecular weight distribution (MWD) was measured using GPC. CHCl ₃ was used as solvent. Shodex-Mikrostyragel (10 ⁵ , 10 ⁴ , 10 ³ , 100 mm ³ ) column sets, RI-detectors, and NMWD polystyrene assays were used. GPC tests were performed at room temperature.

Silicone fluids or gums may comprise, for example, up to 50% by weight of fumed silica fillers of the type commonly used to reinforce silicone rubbers.

Copolymers of olefins, preferably ethylene and at least one silicone-group containing comonomer, are preferably vinyl unsaturated polybishydrocarbysiloxanes or acrylate or methacrylate modifications according to formulas (II) and (III) Hydrocarbyl siloxane has been:

In the above formulas (II) and (III)

n is from 1 to 1000,

R and R 'are independently vinyl, branched or unbranched alkyl of 1 to 10 carbon atoms; Aryl having 6 or 10 carbon atoms; Alkylaryl having 7 to 10 carbon atoms; Or arylalkyl having 7 to 10 carbon atoms,

R ″ is hydrogen or an alkyl chain.

Such compounds are disclosed, for example, in WO 98/12253, the contents of which are incorporated herein by reference.

Preferably, component (B) is preferably a polydimethylsiloxane having M _n of about 1,000 to 1,000,000, more preferably 200,000 to 400,000, and / or a copolymer of ethylene and vinyl polydimethylsiloxane. These components (B) are preferred because they are commercially available.

The term "copolymer" is used herein to mean copolymers produced by copolymerization or by grafting monomers onto the polymer backbone.

Preferably, the silicone-group containing compound (B) is 0.5 to 40% by weight, more preferably 0.5 to 20% by weight, even more preferably 0.5 to 10% by weight, most preferably 1 to 1, of the total amount of the composition in the composition Present in an amount of 5% by weight.

Also preferably, the silicon-group containing compound is added so that the amount of the silicone-group in the total amount of the composition is 1 to 20% by weight, more preferably 1 to 10% by weight.

Preferably, the inorganic filler (C) is present in the composition in an amount greater than 10% by weight, more preferably at least 20% by weight, even more preferably at least 30% by weight, most preferably at least 35% by weight.

Also preferably, the inorganic filler (C) is present in the composition in an amount of up to 70% by weight, more preferably up to 60% by weight and most preferably up to 55% by weight.

Inorganic filler materials suitable for use in component (C), ie, the composition, include all filler materials known in the art. Component (C) also includes any mixture of such filler materials. Examples of such filler materials include oxides, hydroxides, and carbonates of aluminum, magnesium, calcium and / or barium.

Preferably, component (C) comprises inorganic compounds of Groups 1 to 13, more preferably Groups 1 to 3, even more preferably Groups 1 and 2 and most preferably Group 2 metals on the periodic table.

The numbering of chemical groups herein follows the IUPAC system in which groups of elementary periodic systems are numbered from 1 to 18.

Preferably, the inorganic filler component (C) comprises a compound which is neither a hydroxide nor a hydrated compound, more preferably consists of it, even more preferably a compound selected from carbonates, oxides and sulfates More preferably, and most preferably comprises carbonate, more preferably.

Preferred examples of such compounds are calcium carbonate, magnesium oxide and huntite Mg ₃ Ca (CO ₃ ) ₄ , particularly preferred examples are calcium carbonate.

Although inorganic filler (C) is preferably neither a hydroxide nor a hydrated compound, it may typically contain a small amount of hydroxide less than 5% by weight, preferably less than 3% by weight of the filler. For example, small amounts of magnesium hydroxide may be present in magnesium oxide. Also, although filler (C) is not a hydrated compound, it can usually contain small amounts of water of less than 3% by weight, preferably less than 1% by weight of the filler. Most preferably, however, hydroxide and / or water are not present in component (C).

Preferably, component (C) of the flame retardant polymer composition of the present invention comprises at least 50% by weight calcium carbonate, and also preferably consists of calcium carbonate.

In order to facilitate processing and to improve the dispersion of the fillers in the organic polymer, the inorganic fillers may include fillers surface-treated with organosilanes, polymers, carboxylic acids or salts and the like. Such coatings usually do not exceed 3% by weight of the filler.

Preferably, the composition according to the invention comprises less than 3% by weight of organo-metal salt or polymer coating.

In addition, other mineral fillers such as glass fibers may be part of the composition.

In a preferred embodiment of the composition according to the invention the composition is

(D) further comprises polypropylene in an amount of 0.1 to 10% by weight of the total amount of the composition.

Preferably, the amount of polypropylene (D) is at least 0.2% by weight, more preferably at least 0.3% by weight and most preferably at least 0.5% by weight of the total amount of the composition.

Also preferably, the amount of polypropylene (D) is 8% by weight or less, more preferably 4% by weight or less and most preferably 3% by weight or less of the total amount of the composition.

Even more preferably, the MFR ₂ of polypropylene (D) measured at 230 ° C. and 2.16 kg according to ISO 1133 is 0.1 to 15 g / 10 min, more preferably 0.5 to 10 g / 10 min.

Preferably, the tensile modulus of polypropylene (D) measured according to ISO 527-2 is 800 to 2000 MPa, more preferably 900 to 1600 MPa.

In a preferred embodiment polypropylene (D) is a propylene heterophasic copolymer containing polypropylene homo- or copolymer as matrix polymer and incorporated ethylene-propylene-rubber.

Heterogeneous propylene copolymers employ conventional catalysts by multi-step polymerization processes of propylene and ethylene and optional alpha-olefins, such as bulk polymerization, gas phase polymerization, slurry polymerization, solution polymerization, or combinations thereof. Can be produced. Heterogeneous copolymers may be prepared in a loop reactor or a combination of loop and gas phase reactors. These processes are well known to those skilled in the art.

Preferred processes are a combination of bulk slurry loop reactor (s) and gas phase reactor (s). First, a propylene mono- or copolymer matrix is prepared in a loop reactor (s) or a combination of loop and gas phase reactors.

The polymer produced in this way is transferred into another reactor, and a mixture of ethylene and propylene is copolymerized into the same catalyst system, resulting in a heterogeneous system consisting of a semicrystalline matrix in which the near amorphous amorphous component is dispersed therein. By obtaining ethylene-propylene-rubber in the disperse phase is produced. Preferably, this polymerization step is carried out in gas phase polymerization.

Suitable catalysts for the polymerization of heterogeneous copolymers are any stereospecific catalysts for propylene polymerization capable of polymerizing and copolymerizing propylene and comonomers at temperatures of from 40 to 110 ° C. and pressures of from 10 to 100 bar. In addition to metallocene catalysts, Ziegler-Natta catalysts are suitable catalysts.

As an alternative to the production of heterogeneous copolymers by the above sequential multistage process, it can be produced by polymerizing the matrix polymer and ethylene-propylene-rubber in separate stages and then melt blending the two polymers.

In this connection "rubber" and "elastic copolymer" are used as synonyms.

Ethylene propylene elastomeric copolymers can be produced by known polymerization processes such as solutions, suspensions, and gas phase polymerizations using conventional catalysts. Ziegler-Natta catalysts in addition to metallocene catalysts are suitable catalysts.

A widely used process is solution polymerization. Ethylene, propylene, and catalyst systems are polymerized in excess hydrocarbon solvent. If stabilizers and oils are used, they are added directly after polymerization. The solvent and unreacted monomers are evaporated off by hot water or steam or mechanical devolatilisation. The crumble form of polymer is dehydrated on a screen or dried in a mechanical press or drying oven. The debris is molded into rolled bales or extruded into pellets.

The suspension polymerization process is a modified process of the bulk polymerization. The monomer and catalyst system are injected into the reactor filled with propylene. The polymerization takes place immediately to form polymer crumbs that are insoluble in propylene. Propylene is evaporated off and the comonomer completes the polymerization process.

Gas phase polymerization techniques consist of one or more vertical fluidised beds. Nitrogen and monomers in gaseous form are introduced into the reactor together with the catalyst and the solid product is transferred periodically. The heat of reaction is removed using a circulating gas that also functions to fluidize the polymer layer. Solvent free, no solvent removal, washing, and drying are required.

The production of ethylene propylene elastomeric copolymers is described, for example, in US 3,300,459, US 5,919,877, EP 0 060 090 A1, and the company publication "DUTRAL, ethylene-propylene elastomers" of EniChem, p 1-4 It is also described in detail in (1991).

Alternatively, an elastic ethylene-propylene copolymer may be used which is commercially available and meets the requirements set forth.

The heterogeneous copolymer is produced by combining the matrix polymer and the elastomeric copolymer in powder or granule form in a melt mixing device.

When using polypropylene random copolymers as matrix polymers for heterogeneous copolymers, preferred comonomers are linear alpha-olefins or branched alpha-olefins such as ethylene, butene, hexene and the like. Ethylene is most preferred in the present invention.

The comonomer content is preferably at most 10% by weight, more preferably from 4 to 8% by weight, based on the total amount of polypropylene irregular copolymers.

However, preferred matrix polymers are polypropylene homopolymers.

In addition, the heterogeneous copolymer preferably comprises ethylene-propylene-rubber in an amount of preferably 35% by weight or less, more preferably 10 to 20% by weight, based on the total weight of the polymer (D).

The ethylene-propylene-rubber preferably has a propylene content of 40 to 80% by weight, more preferably 45 to 60% by weight, based on the total amount of ethylene-propylene-rubber.

The ethylene-propylene rubber may further comprise alpha-olefin monomer units other than ethylene and propylene monomer units. However, the ethylene-propylene rubber is preferably composed of ethylene and propylene monomer units.

The composition according to the invention can be cross-linked. It is well known to cross-link thermoplastic polymer compositions using crosslinking agents, such as irradiation or organic peroxides, so that the compositions according to the invention may comprise conventional amounts of crosslinking agents. The silane cross-linked polymer may comprise a silanol condensation catalyst.

In addition to components (A)-(D), the compositions of the present invention also usually contain additional conventional polymer components, such as small amounts of antioxidants or UV stabilizers, usually less than 10% by weight, more preferably 5% by weight. It may comprise less than%.

The flame retardant polymer composition of the present invention,

a) preparing a master batch comprising a silicone-group containing compound, an additive, and a polymer and then blending it with an inorganic filler and a matrix polymer,

b) can be prepared by combining all the components in a single step.

For mixing, conventional blending or blending equipment, such as a Banbury mixer, a 2-roll rubber mill, a Buss-co-kneader or a twin screw extruder (twin screw extruder) can be used.

Preferably, the compositions are prepared by blending them together at a temperature high enough to soften and plasticize the polymer, usually from 120 to 200 ° C.

The flame retardant compositions of the present invention can be used in many different applications and products. The composition may for example be molded, extruded, or form moldings, sheets and fibers.

The present invention therefore further relates to articles comprising the flame retardant polymer compositions of any of the above embodiments.

In particular, the present invention relates to a wire or cable comprising a layer made of the flame retardant composition of any of the above embodiments, and thus to the use of the flame retardant polymer composition of any of the above embodiments for producing a layer of wire or cable.

Preferably, the polymer composition is extruded to form a flame retardant layer of wire or cable. This is preferably done at a line speed of at least 20 m / min, more preferably at least 60 m / min, most preferably at least 100 m / min.

The pressure used for the extrusion is preferably 50 to 500 bar.

The invention is further illustrated by the following examples.

1.Measuring method

a) Confocal Laser Scanning Microscopy

Confocal laser scanning microscopy using Leica TCS-SP assessed improved surface smoothness and reduced melt fracture. The irradiation area was 500 x 500 micrometers and the wavelength of the laser beam was 488 nm. HC PL APO 20 x / 0.70 was used as the lens and the resolution was 279 nm in the xy-direction and 768 nm in the xz-direction. The step size of the test was 486 nm.

The resolution of the z-Table was 40 nm and the z-standard (for functional control and validation) was obtained from Rommelwerke with an R _max of 0.97 microns. It was.

b) Melt Flow Rate

Melt flow rates MFR ₂ were measured according to ISO 1133 at 190 ° C. and 2.16 kg loads for polyethylene and 230 ° C. and 2.16 kg loads for polypropylene.

c) tensile modulus

Tensile modulus was determined according to ISO527-2.

d) molecular weight distribution and long chain branching

G 'was determined using the following procedure. This procedure should be followed when determining the side chain variable g 'according to the invention.

Gel Permeation Chromatography (GPC) was used to determine molecular weight (M), molecular weight distribution (M _w / M _n ), intrinsic viscosity [η], and long chain side chain (LCB) content g '.

Gel permeation chromatography, also known as Size Exclusion Chromatography (SEC), is an analytical technique that separates molecules by size. Larger molecules elute first and smaller molecules later.

Elution is carried out in decreasing order of hydrodynamic volume V _h . This can be described as the product of the molecular weight (M) and its intrinsic viscosity [η].

The principle of Universal Calibration in GPC states is that as a function of the elution volume (or time) under given solvent and temperature conditions, the polymer sample is separated by a pure size mechanism (without adsorption or other effects). The logarithm of the hydrodynamic volume of a polymer molecule is the same for all linear or side chain polymers.

See the following equation:

V _h = [η] x M or log V _h = log ([η] x M)

Hydrodynamic volume is defined as the product of intrinsic viscosity [η] and molecular weight M.

The universal assay is independent of the polymer type and side chain potential of the polymer.

A series of small standards was used to confirm the relationship between residence time and molecular weight.

By the Mark-Houwink-Sakurade equation, the polymer intrinsic viscosity is related to its viscosity average molecular weight M _v .

[η] = K x M ^a _v

[η] is the intrinsic viscosity.

M _v is the viscosity average molecular weight.

K and a are Mark-Hockink constants. These constants are dependent on the polymer type, solution, and temperature.

Taking the logarithm of both sides of the equation gives the following equation:

log [η] = logK + ax logM _v

Showing log [η] against log [M _v ] (narrow standards) yields the slope and intercept K.

If K and a are known for both the standard and the sample, the relationship to their respective constants can be used to determine the molecular weight.

GPC uses a universal assay for quantitative evaluation of molecular weight distribution.

The test calculates a universal test curve based on the narrow standard. Calculate the residence time (RI peak) of each standard. These numerical values are used together with the corresponding molecular weights to create a universal calibration curve.

For both RI- and viscosity-detectors, software can be used to show Log viscosity versus Log molecular weight. Each detector yields a universal assay for each fraction in the polymer chromatogram.

Pluripotency assays give genuine molecular weight results.

The software can determine K and a for the standard.

The use of the following values is recommended.

PS: K = 9.95 ^* 10 ^-5 a = 0.725

PE: K = 3.92 ^* 10 ^-4 a = 0.725

The equipment used was a Waters 150CVplus gel permeation with a differential Refractive Index (dRI) detector and a single capillary viscometer detector and three HT6E Styragel (porous styrenedivinylbenzene) columns obtained from Waters. Chromatography no. W-4412 (comparative: Waters 150 CVplus viscometer reinforcement). A calibration curve was created with a narrow molecular weight distribution polystyrene standard (a1116_05002) with different molecular weights. The mobile phase was 1,2,4-trichlorobenzene (purity 98.5%) with 0.25 g / l 2-tert-butyl-4-methylphenol (BHT) added as antioxidant. G '(LCB) was calculated using Waters Millennium ³² version 4 software.

Viscosity low plots were determined for the polystyrene standards that represent linear (non-branched) polymers as there are no long chain side chains, and the branched polyethylene compositions of the present invention. The side chain variables were then calculated from the equation:

g '= [η] _{side chain} / [η] _linear ,

Wherein the [η] _{side chain} is the intrinsic viscosity of the side chain polymer in question, and the [η] _linear is the intrinsic viscosity of the linear (non-branched) standard polymer.

e) shear thinning index

Shear thinning index SHI _{( eta0 .05 / eta300 )} was determined by dynamic rheology on a plate / plate rheometer.

This property can be measured as the ratio of the viscosity at two different shear stresses. In the present invention, shear stress (or G ^* ) at 0.05 kPa and 300 kPa was used to calculate SHI _{( eta0.05 / eta300 )} , which measures the area of the molecular weight distribution.

SHI _{( eta0 .05 / eta300 )} = (eta _{0 .05} / eta ₃₀₀ )

Where eta _{0 .05} / is the complex viscosity at G ^* = 0.05 kPa

eta ₃₀₀ is the complex viscosity at G ^* = 300 kPa.

This was measured by oscillating-frequency sweep in Physica MCR300. The temperature was 170 ° C. and the frequency range was 0.1-500 rad / s. Strain was set at 5%.

2. Formulation of Composition

Busskneader, a flame retardant polymer composition was produced by combining the components together within 200 mm.

The following compositions were prepared:

Composition 1:

Butylacrylate (BA) content of 8.7% by weight, MFR ₂ = 0.45 g / 10 min, M _w / M _n = 50, g '= 0.24, SHI _{( eta0 .05 / eta300 )} = 102.9 56 wt% ethylene butylacrylate copolymer;

85% by weight of propylene homopolymer as matrix, 15% by weight of ethylene propylene rubber as dispersed phase, of which 7% by weight is ethylene units, MFR ₂ = 1.3 g / 10 min, d = 0.908 g / cm ³ , 2% by weight of heterogeneous propylene copolymer with tensile modulus = 1300 MPa;

12% by weight silicone masterbatch containing 40% by weight polysiloxane;

30 weight percent chalk;

The composition had a MFR ₂ (190 ° C., 2.16 kg) of d = 1.153 g / cm ³ , and 0.46 g / 10 min.

Composition 2:

Ethylene butylacrylate copolymer with a BA content of 8% by weight, MFR ₂ = 0.45 g / 10 min, M _w / M _n = 50, g '= 0.24, SHI _{(eta0.05 / eta300)} = 102.9 weight%;

12% by weight silicone masterbatch containing 40% by weight polysiloxane;

Chalk 30 weight percent;

The composition had d = 1.156 g / cm ³ , and MFR ₂ (190 ° C., 2.16 kg) of 0.41 g / 10 min.

Composition 3 (comparative):

Ethylene butylacrylate copolymer 58 with a BA content of 8.1 wt%, MFR ₂ = 0.45 g / 10 min, M _w / M _n = 17, g '= 0.41, SHI _{(eta0.05 / eta300)} = 92.6 weight%;

12% by weight silicone masterbatch containing 40% by weight polysiloxane;

Chalk 30 weight percent;

The composition had a MFR ₂ (190 ° C., 2.16 kg) of d = 1.140 g / cm ³ , and 0.39 g / 10 min.

Composition 4:

Ethylene butylacrylate copolymer with a BA content of 8% by weight, MFR ₂ = 0.45 g / 10 min, M _w / M _n = 50, g '= 0.24, SHI _{(eta0.05 / eta300)} = 102.9 weight%;

6.25% by weight of a silicone masterbatch containing 40% by weight of polysiloxane;

Chalk 30 weight percent;

The composition had a MFR ₂ (190 ° C., 2.16 kg) of d = 1.149 g / cm ³ , and 0.51 g / 10 min.

Cables were made on a laboratory extrusion line. The composition was extruded on a 7 mm nylon rope and the insulator thickness was 1 mm. Tube-on dies were used and linear velocities were 25 and 50 meters per minute. The laboratory extrusion line was equipped with seven temperature zones (120, 140, 150, 160, 170, 170, 170 ° C.).

Table 1 below shows the ratio of the surface (3D) to area (2D) to the area (2D), which is a measure of the surface quality, the lower the ratio, the better the surface quality. The surface area was also examined by visual and tactile sense. The numerical value from the ratio of the surface 3D to the area 2D corresponds to visual and tactile irradiation.

sample MWD of PE (M _w / M _n ) G 'of PE Amount of polypropylene The ratio of the surface 3D to the area 2D Composition 1 50 0.24 2 wt% 1.59 Composition 2 50 0.24 - 1.63 Composition 3 (comparative) 17 0.41 - 2.13 Composition 4 50 0.24 - 1.49

If the ratio of the surface 3D to the area 2D is high, it means that the surface is rough. Therefore, the surface of the composition of the present invention is significantly superior to the surface of the comparative example.

Claims (21)

(A) a polyolefin comprising a polyolefin having a molecular weight distribution M _w / M _n > 20, (B) a silicon-group containing compound, and (C) inorganic filler material Flame retardant polymer composition containing. The flame retardant composition of claim 1 wherein the amount of component (A) is 30 to 70 weight percent of the total amount of the polymer composition. The flame retardant composition of claim 1 wherein component (A) comprises a polyolefin having a molecular weight distribution M _w / M _n > 25. The flame retardant polymer composition of claim 1 wherein component (A) comprises a polyolefin having a g 'value of 0.35 or less. The flame retardant polymer composition of claim 1, wherein component (A) comprises a polyolefin having a shear thinning index (SHI) eta _0.05 / eta ₃₀₀ of at least 70. The flame retardant composition of claim 1 wherein component (A) comprises a polyolefin having a polar group. The method of claim 6 wherein the polyolefin with polar groups C ₁ - to C ₆ - alkyl acrylates, C ₁ - to C ₆ - alkyl methacrylates, acrylic acid, methacrylic acid, and at least one comonomer selected from vinyl acetate, And a copolymer of an alpha-olefin monomer, or an ionomer thereof. 7. Flame retardant composition according to claim 6, wherein the polyolefin having polar groups is present in an amount of at least 50% by weight of the total weight of component (A). The flame retardant composition of claim 1 wherein the amount of component (B) is from 1 to 20% by weight of the total amount of the polymer composition. The flame retardant composition of claim 1 wherein component (B) is a copolymer of ethylene with at least one other comonomer comprising a silicone fluid or gum, and / or a silicone group. The flame retardant composition of claim 1 wherein component (B) comprises polydimethylsiloxane and / or a copolymer of ethylene and vinyl-polymethylsiloxane. The flame retardant polymer composition of claim 1 wherein the amount of inorganic filler (C) is from 20 to 60% by weight of the total amount of the polymer composition. delete The flame retardant polymer composition of claim 1 wherein the inorganic filler (C) comprises carbonates, oxides, and / or sulfates of Group 1-13 elements on the periodic table. The flame retardant composition of claim 1 wherein component (C) comprises a metal carbonate. The composition of claim 1 wherein the composition is (D) The flame retardant composition further comprising polypropylene in an amount of 0.1 to 10% by weight based on the total amount of the composition. The flame retardant polymer composition of claim 16 wherein the MFR ₂ of component (D) measured at 230 ° C. and 2.16 kg according to ISO 1133 is 0.1 to 15 g / 10 min. 17. The flame retardant polymer composition of claim 16, wherein component (D) comprises a polypropylene homo- or copolymer as matrix polymer and a propylene heterophasic copolymer containing incorporated ethylene-propylene-rubber. An article containing a flame retardant polymer composition according to any one of claims 1 to 12 and 14 to 18. 19. A wire or cable comprising a layer made of a flame retardant composition according to any one of claims 1 to 12 and 14 to 18. delete